The Cardinals added four prospects to their 40-man roster on Rule 5 protection day: Outfielder Joshua Baez, catcher Leonardo Bernal, and left-handers Cooper Hjerpe and Brycen Mautz. They needed to open one spot, so they designated reliever Jorge Alcala for assignment.
St. Louis signed Bernal as an international free agent in 2021. MLB.com ranks him 4th among the organization’s prospects. Bernal hit .270 with 10 home runs over 96 games at High-A in 2024, earning a bump to Double-A. He scuffled to a 64 wRC+ in a brief sample with Springfield. Bernal was back with the Double-A squad this past season. He put together a league-average performance in terms of wRC+, while chipping in 13 home runs and 13 steals. The 21-year-old has shown decent base-stealing prowess for a catcher, swiping 20 bags over the past two years.
The Cardinals selected Baez in the second round of the 2021 draft. He’s the team’s 11th-ranked prospect on MLB.com. A bloated strikeout rate held Baez back in his first few professional seasons, but he got the contact in check this past season. After three straight years with a strikeout rate above 34%, Baez trimmed it to 20.6% across two levels in 2025. He also showed a new level of power, reaching 20 home runs between High-A and Double-A. Baez had totaled 24 home runs in his previous four professional seasons. He also racked up 54 stolen bases this past year.
Hjerpe is one of the team’s top arms in the minors, but he’s currently on the shelf after undergoing Tommy John surgery back in April. The lefty sits at 13th on MLB.com’s prospect list. Hjerpe was a first-rounder back in 2022. He posted a solid 3.27 ERA between High-A and Double-A in 2024. Hjerpe had a strikeout rate above 35% at both stops.
Mautz was taken in the second round back in 2022. He’s immediately jumped into a workhorse role as a professional, making at least 23 starts in all three of his seasons. Mautz struggled to a 5.18 ERA at High-A in 2024, but bounced back with his best season yet this past year. The lefty posted a 2.98 ERA with a career-best 28.6% strikeout rate across 114 2/3 innings at Double-A in 2025. The 24-year-old is a candidate to make starts at the big-league level at some point next season.
Alcala was claimed off waivers from the Red Sox back in August. He was knocked around in 15 appearances with the Cardinals, recording a 5.02 ERA. The 30-year-old had spent his entire MLB career with the Twins heading into 2025. He was dealt to Boston in June and made 19 appearances for the team before being designated for assignment and landing in St. Louis.
